1. Field of the Invention
This invention relates to an improved bounce crimp texturized multi-filament thermoplastic yarn and to methods and apparatus for making such yarns. In a further aspect this invention relates to a bounce crimp texturizing and fluid vortex interlacing process and apparatus for making bounce crimped yarn having improved fiber-fiber stability. In another aspect, the invention relates to a bounce crimped yarn substantially free from filament loops and entanglement and a modified bounce crimper for making yarn.
2. The Prior Art
Synthetic thermoplastic yarn materials are produced as a number of continuous, straight, smooth filaments. Such yarns have little bulk, and their utility in textile applications is thus rather limited.
In order to enhance the bulk and texture of synthetic yarns, a variety of crimping processes have been used in the past. One common technique which has been used for thermoplastic yarns is to bend the yarn filaments and heat the yarn while the filaments are in bent or crimped configurations, commonly referred to as false twist texturizing; note, for example, U.S. Pat. Nos. 3,932,986 and 3,946,546. Another type of texturizing is fluidized texturizing such as, for example, described in U.S. Pat. No. 2,869,976 and stuffer box crimping such as, for example, described in U.S. Pat. No. 4,081,886.
One especially good texturizing technique, in terms of yielding a high-bulked yarn, is known as "rebound" or "bounce crimping" such as for example described in U.S. Pat. No. 3,665,567.
Thermoplastic yarn texturized by the foregoing bounce crimping process possesses, inter alia, exceptional covering and as such is an especially desirable yarn. It should also be appreciated that bounce crimping yields a recognized type of texture, or crimp, different, for example, from that obtained by other forms of texturizing (e.g., stuffer box).
However, for certain application it would be desirable to increase the fiber stability, or fiber to fiber cohesiveness of this yarn.
Various methods of generally increasing yarn stability are known to the art including, the use of adhesives, twisters, and fluid interlacers such as, for example, described in U.S. Pat. Nos. 3,110,151; 3,116,588; 3,279,164 and 3,875,625. These interlacers operate by causing the yarn to pass through turbulent fluid vortexes causing the yarn to separate into groups of fibers which then interlace with each other forming a stable yarn. Different colored yarns have also been combined via texturizing, twisting and entangling such as shown in U.S. Pat. No. 3,460,336.
In attempting to improve the stability of bounce crimped yarn via fluid interlacing, I discovered that normal bounce crimped yarn could not be directly fluid interlaced effectively.
U.S. Pat. No. 3,703,753 discloses a process for texturizing and entangling thermoplastic yarn. Patentee teaches that after texturizing the yarn must be tensioned to remove a portion of the crimp prior to entangling and further teaches that where fluid texturizing is used it is preferable to use both a pretensioner and tensioner before entangling.
U.S. Pat. No. 3,975,484 discloses a process for drawing, fluid texturizing, and interlacing polyamide yarns, which requires the use of yarns having fiber having noncircular cross-sections and the use of nonaqueous oiling agent prior to drawing and a one-sided yarn heat treatment during drawing. More significantly, it is also apparent that the yarn is tensioned between texturizing and entangling when the yarn passes over the tensioning guide and through the take-up rolls.